Applications were found recently where the analy-
sis of dynamic systems with a special structure could be simp
li-
fied considerably by transforming them into equivalent syst
ems
having complex coefficients and half the number of poles. The
design of controllers for such systems can be simplified in th
e
complex representation, but requires techniques suitable
for
systems with complex coefficients. In the paper, the extensi
on
of the classical root locus method to systems with complex
coefficients is presented. The results are applied with some
advantages to a three-phase controlled rectifier.